<!--
     Any copyright is dedicated to the Public Domain.
     http://creativecommons.org/publicdomain/zero/1.0/
-->
<svg xmlns="http://www.w3.org/2000/svg" width="600px" height="300px">
  <!-- From https://bugzilla.mozilla.org/show_bug.cgi?id=1203376 -->
  <defs>
    <!-- the filter lights are intentionally chosen to fill the entire area with
         a solid color since we're only testing the extents of the filter region
    -->
    <filter id="diffuse" x="-50%" y="-50%" width="200%" height="200%">
      <!-- gives a black filter region -->
      <feDiffuseLighting lighting-color="black">
        <feDistantLight />
      </feDiffuseLighting>
    </filter>

    <filter id="specular" x="-50%" y="-50%" width="200%" height="200%">
      <!-- gives a white filter region -->
      <feSpecularLighting lighting-color="white" specularConstant="100">
        <feDistantLight elevation="90"/>
      </feSpecularLighting>
    </filter>
  </defs>

  <rect x="100" y="100" width="100" height="100" filter="url(#diffuse)" />

  <rect x="340" y="40" width="220" height="220" fill="grey" />
  <rect x="400" y="100" width="100" height="100" filter="url(#specular)" />
</svg>
